273 research outputs found
Cavity state preparation using adiabatic transfer
We show how to prepare a variety of cavity field states for multiple
cavities. The state preparation technique used is related to the method of
stimulated adiabatic Raman passage or STIRAP. The cavity modes are coupled by
atoms, making it possible to transfer an arbitrary cavity field state from one
cavity to another, and also to prepare non-trivial cavity field states. In
particular, we show how to prepare entangled states of two or more cavities,
such as an EPR state and a W state, as well as various entangled superpositions
of coherent states in different cavities, including Schrodinger cat states. The
theoretical considerations are supported by numerical simulations.Comment: 11 pages, 9 figures. Accepted in Phys. Rev.
The efficiency of ultrasonic-assisted extraction of cyanocobalamin is greater than heat extraction
Cyanocobalamin, like other water-soluble vitamins, is susceptible to degradation due to exposure to heat, UV, oxygen and pH. Built on our previous finding, this study aimed to assess the extraction efficiency of cyanocobalamin from dietary supplements. Particularly, cyanocobalamin extraction in a 100 °C water bath was compared with ultrasonic-assisted extraction, with and without the addition of 1 mg/L sorbitol, xylitol and erythritol. Ground defatted samples of supplement tablets were initially treated for 15 min, centrifuged and filtered before quantitative HPLC analysis. Addition of sorbitol and xylitol significantly minimised the thermal degradation during extraction in a 100 °C water bath, as shown in measured cyanocobalamin (~145 μg/tablet) that was higher than the control (100 μg/tablet, p 0.05). Overall, mean cyanocobalamin in sonicated samples was higher than heat-extracted counterparts, suggesting that extraction in a 100 °C water bath was likely to cause thermal degradation. It was possible that ultrasonic-assisted extraction had no effect on cyanocobalamin stability and would lead to a higher extraction efficiency. Therefore, 15 min extraction in an ultrasonic bath can be suggested to be adequate to release cyanocobalamin before its quantitative determination
The Conal representation of Quantum States and Non Trace-Preserving Quantum Operations
We represent generalized density matrices of a -complex dimensional
quantum system as a subcone of a real pointed cone of revolution in
, or indeed a Minkowskian cone in .
Generalized pure states correspond to certain future-directed light-like
vectors of . This extension of the Generalized Bloch
Sphere enables us to cater for non-trace-preserving quantum operations, and in
particluar to view the per-outcome effects of generalized measurements. We show
that these consist of the product of an orthogonal transform about the axis of
the cone of revolution and a positive real linear transform. We give detailed
formulae for the one qubit case and express the post-measurement states in
terms of the initial state vectors and measurement vectors. We apply these
results in order to find the information gain versus disturbance tradeoff in
the case of two equiprobable pure states. Thus we recover Fuchs and Peres'
formula in an elegant manner.Comment: 11 pages, revtex, v3: some typos correcte
Aroma characteristics of lupin and soybean after germination and effect of fermentation on lupin aroma
Greater human consumption of Australian sweet lupin (Lupinus angustifolius) and other legume products such as soybean (Glycine max) is often limited due to undesirable beany flavor. The impacts of germination of lupin and soybean seeds and fermentation of lupin flour on aroma profiles were compared by gas chromatography olfactometry using trained sensory assessors. Untreated soybean compared to untreated lupin had significantly higher concentrations of volatiles commonly associated with beany flavor in legumes; (E)-2-hexanal, (E)-2-octenal, 1-octen-3-one, 1-hexanol and 1-heptanol. After germination of lupin and soybean, 2-methylbutanal was the most abundant volatile, increasing meaty and brothy odor characteristics. Germination of lupin and soybean also increased sweet, woody, mushroom and baked aroma notes. Fermentation of lupin increased mushroom, soil, green and nutty aroma characteristics, however beany odor did not decrease. Germination and to a lesser extent fermentation, may be successful strategies to increase the acceptability of legume flavor
Adiabatic population transfer in a three-level system driven by delayed laser pulses
We give a simple analytic solution that describes a novel method for population transfer in a three-level system driven by delayed pulses and which accounts for recent experimental results. This solution describes a procedure that is counter intuitive, and yet it is shown to be, in fact, one of the simplest solutions for multilevel systems arising from the adiabatic theorem. Its possible application to many-level systems is suggested
Characterizing Planetary Orbits and the Trajectories of Light
Exact analytic expressions for planetary orbits and light trajectories in the
Schwarzschild geometry are presented. A new parameter space is used to
characterize all possible planetary orbits. Different regions in this parameter
space can be associated with different characteristics of the orbits. The
boundaries for these regions are clearly defined. Observational data can be
directly associated with points in the regions. A possible extension of these
considerations with an additional parameter for the case of Kerr geometry is
briefly discussed.Comment: 49 pages total with 11 tables and 10 figure
Adiabatic following criterion, estimation of the nonadiabatic excitation fraction and quantum jumps
An accurate theory describing adiabatic following of the dark, nonabsorbing
state in the three-level system is developed. An analytical solution for the
wave function of the particle experiencing Raman excitation is found as an
expansion in terms of the time varying nonadiabatic perturbation parameter. The
solution can be presented as a sum of adiabatic and nonadiabatic parts. Both
are estimated quantitatively. It is shown that the limiting value to which the
amplitude of the nonadiabatic part tends is equal to the Fourier component of
the nonadiabatic perturbation parameter taken at the Rabi frequency of the
Raman excitation. The time scale of the variation of both parts is found. While
the adiabatic part of the solution varies slowly and follows the change of the
nonadiabatic perturbation parameter, the nonadiabatic part appears almost
instantly, revealing a jumpwise transition between the dark and bright states.
This jump happens when the nonadiabatic perturbation parameter takes its
maximum value.Comment: 33 pages, 8 figures, submitted to PRA on 28 Oct. 200
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